Conventionally, a three mode linear power amplifier requires multiple output switches to realize three modes. Multiple switches require substantial space (die area), and this is a serious problem. Using a single switch would use about 40% less die area, and will have additional advantages over conventional systems.
Switch(es) are used to change between conductive and non-conductive states. Each switch needs proper sizing to reduce on-state loss, proper logic control and peripheral matching circuits. Reducing the number of switches thus reduces die area.